package org.smart4j.chapter2.helper;

import org.apache.commons.dbcp2.BasicDataSource;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.slf4j.LoggerFactory;
import org.slf4j.Logger;
import org.smart4j.chapter2.util.CollectionUtil;
import org.smart4j.chapter2.util.PropsUtil;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Properties;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanListHandler;

public final class DatabaseHelper {

    private static final BasicDataSource DATA_SOURCE;
    private static final QueryRunner QUERY_RUNNER;
    private static final Logger LOGGER= (Logger) LoggerFactory.getLogger(DatabaseHelper.class);
    private static final ThreadLocal<Connection> CONNECTION_HOLDER;
//    private static final String DRIVER;
//    private static final String URL;
//    private static final String USERNAME;
//    private static final String PASSWORD;
    static {
        CONNECTION_HOLDER=new ThreadLocal<Connection>();
        QUERY_RUNNER=new QueryRunner();
        Properties conf= PropsUtil.loadProps("config.properties");
        String driver=conf.getProperty("jdbc.driver");
        String url=conf.getProperty("jdbc.url");
        String username=conf.getProperty("jdbc.username");
        String password=conf.getProperty("jdbc.password");

        DATA_SOURCE=new BasicDataSource();
        DATA_SOURCE.setDriverClassName(driver);
        DATA_SOURCE.setUrl(url);
        DATA_SOURCE.setUsername(username);
        DATA_SOURCE.setPassword(password);

//        try{
//            Class.forName(DRIVER);
//        } catch (ClassNotFoundException e) {
//            LOGGER.error("cannot load jdbc driver",e);
//        }

    }
    /*获取数据库连接*/
    public static Connection getConnection() {
        Connection conn=CONNECTION_HOLDER.get();
        if(conn==null) {
            try {
                conn=DATA_SOURCE.getConnection();
            } catch (SQLException e) {
                LOGGER.error("get connection failure",e);
                throw new RuntimeException(e);
            } finally {
                CONNECTION_HOLDER.set(conn);
            }
        }
//        Connection conn=null;
//        try{
//            conn= DriverManager.getConnection(URL,USERNAME,PASSWORD);
//        } catch (SQLException e) {
//            LOGGER.error("get connection failure",e);
//            throw new RuntimeException(e);
//        } finally {
//            CONNECTION_HOLDER.set(conn);
//        }
        return conn;
    }
    /*关闭数据库连接*/
    public static void closeConnection() {//
         Connection conn=CONNECTION_HOLDER.get();
        if(conn!=null) {
            try{
                conn.close();
            }catch (SQLException e) {
                LOGGER.error("close connection failure",e);
                throw new RuntimeException(e);
            } finally {
                CONNECTION_HOLDER.remove();
            }
        }
    }
    /*查询实体列表*/
    public static final <T> List<T> queryEntityList(Class<T> entityClass,String sql,Object... params) {
        List<T> entityList;
        try{
            Connection conn=getConnection();
            entityList=QUERY_RUNNER.query(conn,sql,new BeanListHandler<T>(entityClass),params);
        } catch (SQLException e) {
            LOGGER.error("query entity list failure");
            throw new RuntimeException(e);
        } finally {
            closeConnection();
        }
        return entityList;
    }
    /*查询实体*/
    public static final <T> List<T> queryEntity(Class<T> entityClass,String sql,Object... params) {
        T entity;
        try{
            Connection conn=getConnection();
            entity=QUERY_RUNNER.query(conn,sql,new BeanHandler<T>(entityClass),params);
        } catch (SQLException e) {
            LOGGER.error("query entity failure",e);
            throw new RuntimeException(e);
        } finally {
            closeConnection();
        }
        return (List<T>) entity;
    }
    /*执行查询语句*/
    public static List<Map<String,Object>> executeQuery(String sql,Object... params) {
        List<Map<String,Object>> result;
        try{
            Connection conn=getConnection();
            result=QUERY_RUNNER.query(conn,sql,new MapListHandler(),params);
        }catch (Exception e) {
            LOGGER.error("execute query failure",e);
            throw new RuntimeException(e);
        }
        return result;
    }
    /*执行SQL文件*/
    public static void executeSqlFile(String filePath) {
        InputStream is=Thread.currentThread().getContextClassLoader().getResourceAsStream(filePath);
        BufferedReader reader=new BufferedReader(new InputStreamReader(is));
        try {
            String sql;
            while ((sql=reader.readLine())!=null) {
                executeUpdate(sql);
            }
        }catch (Exception e){
            LOGGER.error("execute sql file failure",e);
            throw new RuntimeException(e);
        }
    }
    /*执行更新语句*/
    public static int executeUpdate(String sql,Object... params) {
        int row=0;
        try{
            Connection conn=getConnection();
            row=QUERY_RUNNER.update(conn,sql,params);
        } catch (SQLException e) {
            LOGGER.error("execute update failure",e);
            throw new RuntimeException(e);
        } finally {
            closeConnection();
        }
        return row;
    }
    /*插入实体*/
    public static <T> boolean insertEntity(Class<T> entityClass,Map<String,Object> fieldMap) {
        if(CollectionUtil.isEmpty(fieldMap)) {
            LOGGER.error("can not insert entity:fieldMap is empty");
            return false;
        }

        String sql="insert into "+getTableName(entityClass);
        StringBuilder columns=new StringBuilder("(");
        StringBuilder values=new StringBuilder("(");
        for(String fieldName : fieldMap.keySet()) {
            columns.append(fieldName).append(", ");
            values.append("?, ");
        }
        columns.replace(columns.lastIndexOf(", "),columns.length(),")");
        values.replace(values.lastIndexOf(", "),values.length(),")");
        sql+=columns+" values "+values;
        Object[] params=fieldMap.values().toArray();
        return executeUpdate(sql,params) == 1;
    }
    /*更新实体*/
    public static <T> boolean updateEntity(Class<T> entiryClass,long id,Map<String,Object> fieldMap) {
        if(CollectionUtil.isEmpty(fieldMap)) {
            LOGGER.error("can not update entity:fieldMap is empty");
            return false;
        }

        String sql="update "+getTableName(entiryClass)+" set ";
        StringBuilder columns=new StringBuilder();
        for(String fieldName:fieldMap.keySet()) {
            columns.append(fieldName).append("=?, ");
        }
        sql+=columns.substring(0,columns.lastIndexOf(", "))+" where id=?";

        List<Object> paramList=new ArrayList<Object>();
        paramList.addAll(fieldMap.values());
        paramList.add(id);
        Object[] params=paramList.toArray();

        return executeUpdate(sql,params) == 1;
    }
    /*删除实体*/
    public static <T> boolean deleteEntity(Class<T> entityClass,long id) {
        String sql="delete from "+getTableName(entityClass)+" where id=?";
        return executeUpdate(sql,id) == 1;
    }

    private static String getTableName(Class<?> entityClass) {
        return entityClass.getSimpleName();
    }



}
